为什么我在甲骨文开的 1g 主机内存只有 503M

我在甲骨文新加坡新开了个免费 AMD 小鸡，系统是 Oracle Linux 9 ，但是内存只有 500M 。问了 Gemini ，说是有 600 多 M 被虚拟层占用了，看了下几年前开的实例有 900M 的内存。现在这个主机随便运行个命令就卡住，然后 Killed 了，这个实例是不是废了，我本来想搭个落地节点的。

[opc@instance-20251121-1609 ~]$ free -h
               total        used        free      shared  buff/cache   available
Mem:           503Mi       194Mi       142Mi       0.0Ki       192Mi       309Mi
Swap:          1.5Gi       155Mi       1.3Gi

[opc@instance-20251121-1609 ~]$ sudo dmesg | grep -i memory
[    0.000000] DMI: Memory slots populated: 1/1
[    0.005604] ACPI: Reserving FACP table memory at [mem 0x3fb79000-0x3fb79073]
[    0.005605] ACPI: Reserving DSDT table memory at [mem 0x3fb7a000-0x3fb7b9cd]
[    0.005606] ACPI: Reserving FACS table memory at [mem 0x3fbdc000-0x3fbdc03f]
[    0.005607] ACPI: Reserving APIC table memory at [mem 0x3fb78000-0x3fb7807f]
[    0.005608] ACPI: Reserving HPET table memory at [mem 0x3fb77000-0x3fb77037]
[    0.005608] ACPI: Reserving WAET table memory at [mem 0x3fb76000-0x3fb76027]
[    0.005609] ACPI: Reserving BGRT table memory at [mem 0x3fb75000-0x3fb75037]
[    0.006132] Early memory node ranges
[    0.165396] PM: hibernation: Registered nosave memory: [mem 0x00000000-0x00000fff]
[    0.165397] PM: hibernation: Registered nosave memory: [mem 0x000a0000-0x000fffff]
[    0.165399] PM: hibernation: Registered nosave memory: [mem 0x00806000-0x00807fff]
[    0.165400] PM: hibernation: Registered nosave memory: [mem 0x00810000-0x008fffff]
[    0.165402] PM: hibernation: Registered nosave memory: [mem 0x3e4b1000-0x3e4b9fff]
[    0.165403] PM: hibernation: Registered nosave memory: [mem 0x3f8ee000-0x3fbfdfff]
[    0.229618] Freeing SMP alternatives memory: 44K
[    0.240785] Memory: 379496K/1042980K available (18432K kernel code, 5924K rwdata, 15108K rodata, 4684K init, 5968K bss, 634464K reserved, 0K cma-reserved)
[    0.240937] x86/mm: Memory block size: 128MB
[    1.972720] Freeing initrd memory: 99512K
[    1.981936] Non-volatile memory driver v1.3
[    2.570263] Freeing unused decrypted memory: 2028K
[    2.570978] Freeing unused kernel image (initmem) memory: 4684K
[    2.571622] Freeing unused kernel image (rodata/data gap) memory: 1276K
[   19.666960] i2c i2c-0: Memory type 0x07 not supported yet, not instantiating SPD
[   23.858184] __vm_enough_memory: pid: 1555, comm: dtprobed, bytes: 1073741824 not enough memory for the allocation
[   23.858200] __vm_enough_memory: pid: 1555, comm: dtprobed, bytes: 1073876992 not enough memory for the allocation
[ 1380.930268]  out_of_memory+0xf3/0x288
[ 1381.241129] Tasks state (memory values in pages):
[ 1382.042297] Out of memory: Killed process 5112 (dnf) total-vm:971060kB, anon-rss:324716kB, file-rss:6356kB, shmem-rss:0kB, UID:0 pgtables:1524kB oom_score_adj:0
[ 1446.027212]  out_of_memory+0xf3/0x288
[ 1446.441223] Tasks state (memory values in pages):
[ 1447.038350] Out of memory: Killed process 5168 (dnf) total-vm:1023660kB, anon-rss:328256kB, file-rss:7160kB, shmem-rss:0kB, UID:0 pgtables:1492kB oom_score_adj:0